nuclei 0.5.2

Proactive IO & runtime system
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137

use core::future::Future;
use core::pin::Pin;
use core::task::Poll;
use std::time::Duration;

use super::sleep;
use crate::rt::context;
use crate::rt::shard::{Limits, Shard};

fn shard() -> Shard {
    Shard::new(Limits {
        max_nesting: 8,
        buffer_cap: crate::buf::DEFAULT_CAP,
        backend: crate::rt::backend::chosen().unwrap(),
    })
    .unwrap()
}

/// Polls `f` once, from inside the shard's loop.
async fn poll_once<F: Future + Unpin>(f: &mut F) -> Poll<F::Output> {
    core::future::poll_fn(|cx| Poll::Ready(Pin::new(&mut *f).poll(cx))).await
}

#[test]
fn a_dropped_sleep_leaves_nothing_armed() {
    let shard = shard();
    let _current = context::enter(&shard);
    shard.block_on(async {
        let mut s = sleep(Duration::from_secs(3600));
        assert!(poll_once(&mut s).await.is_pending());
        assert_eq!(shard.wheel().borrow().armed(), 1);
        drop(s);
        assert_eq!(shard.wheel().borrow().armed(), 0);
    });
}

#[test]
fn a_finished_sleep_leaves_nothing_in_the_wheel() {
    let shard = shard();
    let _current = context::enter(&shard);
    shard.block_on(async {
        sleep(Duration::from_millis(2)).await;
        assert_eq!(shard.wheel().borrow().armed(), 0);
    });
}

#[test]
// The block hands the armed sleep out on purpose, to drop it elsewhere.
#[allow(clippy::async_yields_async)]
fn a_sleep_dropped_on_another_thread_is_removed_by_its_shard() {
    let shard = shard();
    let _current = context::enter(&shard);
    let s = shard.block_on(async {
        let mut s = sleep(Duration::from_secs(3600));
        assert!(poll_once(&mut s).await.is_pending());
        s
    });
    assert_eq!(shard.wheel().borrow().armed(), 1);
    std::thread::spawn(move || drop(s)).join().unwrap();
    // The removal waits in the shard's mailbox until its next look.
    shard.block_on(async {
        sleep(Duration::from_millis(1)).await;
    });
    assert_eq!(shard.wheel().borrow().armed(), 0);
}

#[test]
fn a_dropped_precise_sleep_leaves_nothing_armed() {
    let shard = shard();
    let _current = context::enter(&shard);
    shard.block_on(async {
        let mut s = super::sleep_precise(Duration::from_secs(3600));
        assert!(poll_once(&mut s).await.is_pending());
        assert_eq!(shard.wheel_of(true).borrow().armed(), 1);
        assert_eq!(shard.wheel().borrow().armed(), 0);
        drop(s);
        assert_eq!(shard.wheel_of(true).borrow().armed(), 0);
    });
}

#[test]
fn a_finished_precise_sleep_leaves_nothing_in_its_wheel() {
    let shard = shard();
    let _current = context::enter(&shard);
    shard.block_on(async {
        super::sleep_precise(Duration::from_micros(300)).await;
        assert_eq!(shard.wheel_of(true).borrow().armed(), 0);
    });
}

#[test]
// The block hands the armed sleep out on purpose, to drop it elsewhere.
#[allow(clippy::async_yields_async)]
fn a_precise_sleep_dropped_on_another_thread_is_removed_by_its_shard() {
    let shard = shard();
    let _current = context::enter(&shard);
    let s = shard.block_on(async {
        let mut s = super::sleep_precise(Duration::from_secs(3600));
        assert!(poll_once(&mut s).await.is_pending());
        s
    });
    assert_eq!(shard.wheel_of(true).borrow().armed(), 1);
    std::thread::spawn(move || drop(s)).join().unwrap();
    shard.block_on(async {
        super::sleep_precise(Duration::from_micros(100)).await;
    });
    assert_eq!(shard.wheel_of(true).borrow().armed(), 0);
}

#[test]
fn a_reset_precise_sleep_is_armed_once_at_its_new_deadline() {
    let shard = shard();
    let _current = context::enter(&shard);
    shard.block_on(async {
        let mut s = super::sleep_precise(Duration::from_secs(3600));
        assert!(poll_once(&mut s).await.is_pending());
        let soon = super::Instant::now() + Duration::from_micros(200);
        Pin::new(&mut s).reset(soon);
        assert_eq!(shard.wheel_of(true).borrow().armed(), 0);
        assert_eq!(s.deadline(), soon);
        (&mut s).await;
        assert!(s.is_elapsed());
        assert!(super::Instant::now() >= soon);
        assert_eq!(shard.wheel_of(true).borrow().armed(), 0);
    });
}

#[test]
fn the_microsecond_wheel_rounds_a_deadline_up_and_never_early() {
    let shard = shard();
    let at =
        crate::time::clock::nanos(crate::time::clock::origin() + Duration::from_nanos(2_000_001));
    assert_eq!(shard.time_of(true, at), 2_001);
    assert_eq!(shard.time_of(false, at), 3);
    let exact = crate::time::clock::nanos(crate::time::clock::origin() + Duration::from_micros(7));
    assert_eq!(shard.time_of(true, exact), 7);
}